TROPICAL WEATHER FORECAST SYNOPSIS…ISSUED AUG. 07, 2016…6:45 P.M. EDT

TROPICAL CYCLONE FORMATION: MONITORING W. ATLANTIC

Disclaimer:  This site is not affiliated with the National Hurricane Center, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, and I am solely responsible for the content.
(T. F. “Storm” Walsh III)

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CURRENT 2016 ATLANTIC TROPICAL CYCLONE TOTALS:

TOTAL STORMS: 5
HURRICANES: 2
INTENSE HURRICANES: 0
U.S.LANDFALLS: 2

StormW’s Seasonal Hurricane Forecast:
TOTAL STORMS: 14-16
HURRICANES: 6-8
INTENSE HURRICANES: 3-4

Good evening everyone!

The weak area of low pressure that was being monitored in the extreme NE GOMEX, has moved inland over the NE Florida peninsula.  Albeit decent convection is noted just offshore the Big Bend area, the actual low can be seen spinning over the peninsula in RGB satellite loop imagery.  Thus ends the probability of a Tropical Depression developing.

GOMEX SATELLITE LOOP IMAGERY
avn-lgomex

rgb-lGOMEX

Based on current steering and satellite loop imagery, steering has currently collapsed, and the low appears to be stationary at the moment.  The WPC QPF forecasts still call for very excessive rainfall totals over the next 5-7 days over portions of W. GA., central and south AL., and SE MS.  I’ll explain…the system had been moving to the NE, before stalling.  Based on my analysis of current forecast steering maps, the low center may remain quasi-stationary for the next 18-24 hours.  It appears WPC is basing the projected QPF amounts over the mentioned areas, as we are currently thinking the entire system may perform a cyclonic loop, which would bring rainfall over the mentioned areas.

WPC QPF FORECAST 5 AND 7 DAYS
p120i

p168i

Residents over those areas and surrounding areas should monitor local NWS statements and advisories regarding the potential for heavy rainfall and possible flash flooding at some locations as steering patterns have shown to change in as little as a 24 hour period.

NWS DOPPLER RADAR LOOPS FROM KTLH AND KTBW
TLH.N0Q.20160807.2147

TBW.N0Q.20160807.2150

The NWS Warning and Advisory map is interactive.  Just click on your area of interest for the latest statements and warnings.

NWS WARNING AND ADVISORY MAP
US

Elsewhere, I am still monitoring the area of disturbed weather in the WATL, located NE of the southern Bahamas area.  While this hasn’t shown any organization at the surface, convection over the past 2 hours has become better organized and a bit more consolidated.  Vorticity at the moment is confined to the mid levels of the atmosphere. The NHC has designated only a LOW (20%) probability of cyclone formation.  Based on my analysis of the current wind shear forecast, and water vapor satellite loop imagery, as the upper level low to the west of this disturbance backs away, upper level winds are forecast to become fairly conducive during the next 24-30 hours, before returning to unfavorable for development.  While I concur with the NHC probability, I do believe this has that small window of opportunity to become a little better organized, and maybe try to develop a good surface reflection, prior to wind shear increasing.

NHC 5 DAY GRAPHICAL TROPICAL WEATHER OUTLOOK
two_atl_5d0

Based on satellite loop analysis and current steering, this disturbance is moving to the NNW, and given its positioning in relation to the ridge, should begin to move more toward the north in about 18 hours, and then eventually off to the NE.

CARIBBEAN SATELLITE LOOP IMAGERY
avn-lcaribbean

CURRENT STEERING LAYER MEAN
wg8dlm1

Elsewhere, another Tropical Wave is getting ready to exit the African continent.  Convection has diminished greatly over the past 6 hours, however I will be keeping tabs on this, as it appears there is another break in the SAL / African dust situation.  The current TPW animation suggests a surge of TPW / Moisture in which this wave may be able to work with.  I will continue to monitor this wave for any significant changes once it gets into the Atlantic.

METEOSAT SATELLITE LOOP
avn-lmeteosat

CIMSS SAL MAP
splitE

Yesterday evening, I mentioned in one of the weather chats I belong to, I would touch on the SAL situation we’ve seen most of the season.  Typically, July has the most numerous and most severe SAL outbreaks.  It would almost seem this season, that an extended period of dust outbreaks has occurred.  Typically, dust rolls out into the Atlantic on average every 3-5 days.  It appears this season, one of the culprits for all of the dust we’ve seen thus far, seems to have been what I feel has been an abnormally stronger Azores Bermuda high, which through June and July, had been parked further south and east, closer to Africa.  This not only produced subsidence, causing a lack of instability, but aided in getting vast amounts of dust into the MDR.  However, you could consider the main factor to be, the lack of any significant rainfall over the NW Sahel region (shown in the graphics).  I’ve provided current 10 day total rainfall forecast maps.  You can see where the greatest rainfall amounts are projected.  This is just south of the Sahel area.  The Sahel region, and northward, is where the African dust originates.  The heavier rainfall amounts have been further south, due to the fact the Gulf of Guinea SST’ anomalies show the Gulf of Guinea anomalies to be warmer than average.  What we need to see, is for the Gulf of Guinea to become cooler, which through the resultant temperature and pressure gradients, allows for the ITCZ or Monsoon Trough to be lifted further north, into the NW Sahel, allowing for more rainfall over that region.  This would aid in cutting down the African dust regime.

AFRICA SATELLITE IMAGERY (DUST CHANNEL…DUST IS PINK/MAGENTA COLORS)…CLICK IMAGE FOR CLOSE UP IMAGE

EUMETSAT_MSG_RGBDust_WesternAfrica

AFRICA SAHEL REGION MAPS
sahel-map
sahel

AFRICA 10 DAY RAINFALL TOTAL FORECAST
gfs_tprecip_westafr_41

cmc_total_precip_afr_41

The ECMWF, GFS, and to some extent, the CMC GGEM tend to indicate lowering 500 mb pressure anomalies near the Cape Verde islands in about 5-6 days.

Now, modeling from NASA still indicates we will continue to see dust in the Atlantic, but with breaks in between at various periods.  I read a good paper from the AMS online journal, authored by Scott A. Braun, with the suggestions that the SAL may not always kill tropical cyclone genesis. However, as we’ve noticed (and through my 15 years of tropical cyclone forecasting), it seems almost 99% of the time, a tropical system will succumb to the SAL.

NASA DUST PROJECTION 7 DAYS
nasa_dust_atlantic_29
NASA DUST PROJECTION 10 DAYS
nasa_dust_atlantic_41
AMS JOURNAL PAPER ON RE-EVALUATING THE ROLE OF THE SAL
http://journals.ametsoc.org/doi/full/10.1175/2009MWR3135.1

Now, albeit the NASA modeling indicates more dust incidents, it does indicate a decent surge of TPW during days 6-10.  If you remember, we followed the TPW surge across the Atlantic a few days to one week ago, which led to the development of Earl, and is aiding the disturbed weather east of the Bahamas.  So, all may not be lost this season.  Again, as I’ve stated a couple of times previously, I’m not looking for much as far as a Cape Verde season, although we could see development in that area later in the season.  In the big picture, looks like we’ll have to rely on tropical waves to slide under the “radar” so to speak (i.e. Earl; current disturbance) for more of close in development type situations.

NASA TPW PROJECTIONS 4, 6 AND 8
nasa_pwat_atlantic_17
nasa_pwat_atlantic_26

nasa_pwat_atlantic_32
I intend to update tomorrow through Wed.

Elsewhere, Tropical Storm formation is not expected during the next 5-7 days

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST
MEMBER WEST CENTRAL FLORIDA AMS
CoCoRAHS OBSERVER

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About palmharborforecastcenter

I am a Tropical Forecast meteorologist, providing hurricane forecasts during the Atlantic Hurricane Season. I retired from the U.S. Coast Guard in July of 2001. Meteorology became my passion in high school, and I have continued my educational background in meteorology since 1996, when I undertook the study of Tropical Meteorology. While working toward my degree, I had to unexpectedly withdraw from college due to my oldest sons medical reasons. I do however, meet the educational criteria of the AMS to be recognized as a meteorologist. Studies include, but are not limited to the Navy Aerographers Mate course, Naval METOC meteorology course, Meteorology 2010 Sophomore level course while attending St. Petersburg College, Clearwater, FL., Basic Forecasting course for operational meteorologists from Rapid WX, meteorology institute, a four month meteorological internship, and extensive research on numerous meteorological topics such as the MJO, NAO, satellite imagery interpretation, etc. I have been forecasting Tropical Weather (Tropical Storms and Hurricanes) since 1996, with my main client being three different Coast Guard Commands.
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5 Responses to TROPICAL WEATHER FORECAST SYNOPSIS…ISSUED AUG. 07, 2016…6:45 P.M. EDT

  1. Monty says:

    Thanks Storm. Agree with LT. A little more action. Glad you’re on it Senior Chief. Stay dry…it looks like the models peed all over the SEUS

  2. dellamom says:

    Thank you, Storm. Good to know you are there interpreting the information for us.

  3. originallt says:

    Thanks so much storm! looks to be getting pretty active across the board! And you take care, Tampa area looks like it’s being hit hard by rain this morning(Monday)!

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